In order to prevent terminal fittings from releasing, there has been developed a connector provided with a retainer as shown in FIG. 1. A plurality of cavities 3 extending in the lateral direction and open to the opposite front and rear walls is formed in housing 1 of the connector. A corresponding plurality of openings 10 in communication with cavities 3 is formed in the upper and lower surfaces thereof. Retainers 8 are disposed above and below housing 1 and are connected therewith via hinges 11. The retainers 8 are movable toward and away from housing 1. Retainers 8 are externally mountable on housing 1 and are provided with a pair of side members 12 at opposite sides, the members being deformable so as to widen the spacing therebetween. Each side member 12 is formed with window 13. On the other hand, recesses 15, engageable with corresponding side members 12, are formed at opposite side surfaces of housing 1. As shown in detail in FIG. 8, two types of projections (first locking projection 17 and second locking projection 18) are formed in each recess 15. When projections 17 engage windows 13, locking portions of retainers 8 enter openings 10, but do not enter cavities 3. In this first locking position, the insertion and withdrawal of terminal fittings 5 are permitted. Retainers 8 are moved toward housing 1 while widening the spacing between each pair of side members 12 so that both projections 17 and 18 are in windows 13. Then, locking portions 9 enter deeply into cavities 3 and engage terminal fittings 5, thereby preventing terminal fittings 5 from coming out (second locking position).
As described above, when retainers 8 shift from the first locking position, where only projections 17 are in windows 13, to the second locking position, where both projections 17 and 18 are in the windows 13, the pairs of side members 12 deform to widen the spacing between each pair. This shift of retainers 8 is shown in detail in FIGS. 9(a) to 9(c). While windows 13 of retainer 8 shift from the first locking position (as shown in FIG. 9(a)) to the second locking position, windows 13 are at least momentarily free of both projections 17 and projections 18 as shown in FIG. 9(b). Accordingly, unless the movement of retainers 8 is carefully controlled, they may be completely disengaged from housing 1, resulting in a cumbersome operation of having to mount retainers 8 on housing 1 again.